After Christmas last year, I was on a train from Pittsburgh to New York and sat next to a man who had just gotten out of prison. He got on the train at Lewisburg, where he had spent the last four and a half years. Now he was headed to Philadelphia to meet his family. He was excited to eat real food again, try yoga, do all the things you can't do inside.
As we pulled in to Philadelphia, he asked me what time it was; I checked my phone and told him the train was a few minutes early. He asked if maybe my phone was early, and I had to tell him that it didn't work that way. It's a phone; it's never early or late. It always knows exactly what time it is. Of course, he'd had a cell phone before he went to Lewisburg — he knew exactly how they worked — but after four years inside, he'd gotten used to a less centralized version of time, abiding by a dozen different analog clocks that never quite synced up. For centuries, that's how time worked, and in some corners of the world, it still works that way.
In 2015, an accurate clock is one that's always connected
In 2015, an accurate clock is one that's always connected to the larger grid — an idea that the Apple Watch carries to its furthest extreme. The precise details of the hardware are still unclear (it’s still Apple, after all), but the press materials boast accuracy within 50 milliseconds of the global time standard, "the same precision found in GPS satellites." (As a footnote reminds us, that depends on regular syncing with the iPhone.) The most accurate route would be to connect directly and continuously to the GPS satellites, which get their time directly from the atomic clocks at the US Naval Observatory, but that would drain the battery too quickly. An indirect route is more likely, saving battery life by connecting periodically to through the iPhone to an Apple server that’s tuned to the atomic clocks. That cuts the accuracy down a little, but you’re still dealing with a fraction of the blink of an eye (roughly one-sixth, for those keeping score).
But how precise is the Apple Watch’s internal clock when it doesn’t have a connection to some of the world’s most accurate time-keeping systems? It's difficult to say. Apple's page talks about "multiple technologies" in addition to connectivity, which will almost certainly make the watch more precise than the iPhone, but it's something of a moot point. If some sort of Butlerian Jihad took out all the time-keeping satellites and servers, your Apple Watch would be useless anyway. This is how all smartwatches work. Virtually every function of the device derives from its connection to the larger network, starting with your phone and ending with the servers that store your email and process your health data. Why would keeping time be any different?
Typically, watches focus on precision rather than accuracy
There are already watches on the market that occasionally synchronize with the world’s atomic clocks by shortwave or GPS signal, but they’re relatively rare, and the Apple Watch is already one of the most prominent devices to keep time by tethering to an outside server. Typically, watches focus on precision rather than accuracy, counting out as exact a second as possible. Perhaps you're in sync with the rest of the world, perhaps you're a few seconds fast — but your time is as internally consistent as possible, with as much claim to legitimate time as anyone. Perhaps you're not a few seconds fast, and it's the rest of the world that's a few seconds slow. It's not an issue of true and false, just equally precise clocks running slightly out of phase, performing the passage of time rather than measuring it.
This is a forgiving way of thinking about time — allowing for whole minutes to slip by in the gap between one person's sense of time and another's — and it’s closer to how we perceive it in our everyday lives. Time perception studies show all sorts of minor distortions. Have a glass of wine, and time will start to pass more quickly. A cup of coffee (or enough excitement to raise your dopamine levels), and the seconds will tick by more slowly. Our mental clocks are unpredictable, and it's rare that they're perfectly synced to the people around us. It's stressful to keep them aligned, whether it's a tight deadline or a rigidly timed lunch hour. We'd rather live on our own time.
Still, if the fight is between loose clocks and tethered ones, the tether's clearly winning. The global time standard is everywhere, and it’s easier than ever to connect to it. Systems like GPS need that precision: a few nanoseconds’ delay in a GPS satellite translates to a location that’s off by as much as a car’s length. What’s surprising is that the rest of us are already coming along for the ride.